Two-stroke cycle internal combustion engine



Oct. 31, 1933. o. BEYER TWO-STROKE CYCLE INTERNAL COMBUSTION ENGINE Fild June 12. 1931 Jwenz'ar 01% Bqyer $7M Patented Oct. 31, 1933 I PATENTiu OFFICE 'rwo-s'raom: crcn: INTERNAL comaus'rron ENGINE Otto Beyer, Munich, Germany Application June 12, 19: in Germany 1, Serial in. 543,995, and May 10. 19:0

2 Claims. (a. 123-51) The present invention relates to a two-stroke cycle internal combustion engine with a slot scavenging and supply of the fuel charge through a hollow stepped piston which in its upper dead point position exposes the admission of the charge to the crank case, and in its lower dead point position effects the outflow of the compressed charge from the crank case into the annular combustion chamber surrounding the piston rod.

The invention is based on the knowledge that these engines in a predominant manner are adapted for the purpose of eifecting external work in the form of a reciprocating movement in' that the hollow piston is closed tightly around its upper end, while the guide member of the combustion cylinder which surrounds it is left open at the top so that the hollow piston rod, which must, be packed in an airtight manner against the guide member, periodically pases out of the combustion engine during the operation of the engine and may serve as a hammer, phmger or other tool or may be connected to such a tool. In this manner, in cases where the operation requires a reciprocating movement, it is unnecessary to convert the rotary movement of the crank from the usual engines into a translating movement and thus the loss in energy coincident therewith is obviated.

In the accompanying drawing is illustrated an example of construction of the invention in which the external work of a two-stroke cycle engine of the character referred to is used for the production of compressed air in a pump cylinder mounted on the working cylinder 01' the engine.

Figure 1 is a vertical section,

Figure 2 is a cross section on the line lI-II of Figure 1, and

Figure 3 is a cross-sectional view of a valve.

In the operating cylinder 2 of the two-stroke cycle engine operates a stepped piston 3 with a hollow piston rod 4, in which there are provided in the known manner the controlling slots or ports 5 which enable the fuel-air mixture flowing into the interior of the piston rod 4 to pass into the annular combustion chamber 6 as soon as the stepped piston 3, 4 has reached the lower dead point position shown in the drawing. In the upper dead point position of the piston the slots 5 are in the position indicated at 5' inside a bush '7 which guides the piston rod 4. when the stepped piston 3, 4 moves upwardly a partial'vacuum is formed in the crank case 8 and as soon as the lower edge 9 of the piston 3 exposes the inlet port 11 communicating with the suction pipe 10 by means of pipe the mixture flows into the crank case 8 and into the hollow stepped piston 3, 4 whereby this is intensively cooled. On the succeeding downward stroke the inlet port 11 is first closed by the piston 3 and the mixture contained in the crank case 8 and in the hollow stepped piston 3, 4 is compressed. As soon as the slots 5 are exposed by the guide bush 7, the mixture flows into the annular combustion chamber 6, while driving before it the residual burnt gases so that these escape through the exhaust slots 12 and the annular passage 31 surrounding these. On the succeeding upward stroke of the stepped piston 3, 4, the slots 5 again come within the guide bush 7, while at the same time the exhaust slots 12 are covered by the piston 3 so that the annularchamber 6 is completely closed and the fuel-airmixture contained therein is compressed on the further upward movement of the piston 3, so as to be ignited in the known-manner near the upper dead point position, whereupon the operation is repeated.

According to the present invention the upper end or the hollow piston rod 4 is closed by a cover 13, while the guide bush '7, against which the rod 4 bears in a fluid-tight manner, is open at its upper end. In this manner the piston rod 4, during the operation of the engine, passes out of the cylinder block 2, '1 in the manner of a plunger and again disappears therein. In the example of construction illustrated, the cover 13 of the piston rod 4 is formed as a double acting piston 14 operating in a cylinder 15 which is secured detachably in a suitable manner to the guide bush 7. The cylinder 15 is provided with inlet valves 16, 1'! and exhaust valves 18,19, of which the valves 16 and 1'1 lead to the outer air, while the valve 18 is connected to a container 20. The outlet valve 19 is connected by a pipe 21 to a three-way cock 22. The second pipe 23 of the three-way cock leads to the compressed air container 20, while the third pipe 24 is connected to the angular combustion chamber 8 by a slot 25 (see also Figure 2). I! by means oi. the threeway cock 22 the pipes 21 and 24 are connected together, then during the downward stroke of the piston 14 the air which was sucked in through.

the valve 1'7 during the preceding upward stroke valve 16 is opened so that air is sucked into the cylinder above the piston 14. On the succeeding upward stroke the valve 16 is closed and the valve 18 is opened, and the air is forced into the container 20. At the same time scavenging air is again sucked through the inlet valve 17 into the chamber underneath the piston 14, so as to be again driven into the combustion chamber 6 in the manner above illustrated during the succeeding downward stroke of the piston. If it is desired to omit the additional scavenging of the engine it is only necessary to set the three-way cock 22 into such a position that it connects together the pipes 21 and 23 in which case the compressed air container 20 is charged during both the downward and the upward strokes. This container is preferably fitted with a gauge 30 and also, if desired, with a safety valve, not shown.

Instead of the three-way cock 22 the pipes 21, 23 and 24 may be provided with a valve which when a predetermined maximum pressure in the container 20 is obtained allows compressed air to pass through the pipes 23 and 24 into the combustion chamber, whereby the excess air is used in an extremely advantageous manner as at the time at which the maximum pressure is obtained the heating of the engine will be at its maximum.

The invention is not limited to the example of construction illustrated. It also includes arrangements in which the hollow piston rod of an engine of the character above referred to is used directly for effecting external work and in which the piston rod is connected to a double acting air pump which on the one hand acts on a compressed air container and on the other hand serves to scavenge and cool the engine. In enzines known hitherto such an additional scavenging is possible only by means of a separate pump coupled to the crank shaft.

I claim:

l. A two-stroke cycle engine, comprising a cylinder, a stepped piston operable therein having a hollow unobstructed piston rod, the interior of said rod being in continuous communication with the crank case, and said piston rod being closed only at its upper end, means for admitting the charge to the crank case side of. the piston at the upper dead point position of the piston, means for conducting the compressed charge at the lower dead point position of the piston from the crank case side to the chamber surrounding the piston rod, means for causing combustion of the chargein said chamber, a double-acting piston at the upper vend of the hollow piston rod, a pump cylinder, and means for securing said double acting piston to the rod, for operating said double-acting piston in the pump cylinder.

2. A two-stroke cycle engine, comprising a cylinder, a stepped piston operable therein having a hollow unobstructed piston rod, the interior of said rod being in continuous communication with the crank case, and said piston rod being closed only at its upper end, means for admitting the charge to the crank case side of the piston at the upper dead point position of the piston, means for conducting the compressed charge at the lower dead point position of the piston from the crank case side to the chamber surrounding the piston rod, means for causing combustion of the charge in said chamber, a double-acting piston at the upper end of the hollow piston rod, a pump cylinder, means for securing said double acting piston to the rod, for operating said double-acting piston in the pump cylinder, and means for conducting compressed air from the pump cylinder to the engine cylinder for the purpose of scavenging the latter.

OTIO BEYER. 

